Honeybees use their wings for water surface locomotion

Honeybees display a unique biolocomotion strategy at the air- water interface. When water's adhesive force traps them on the surface, their wetted wings lose ability to generate aerodynamic thrust. However, they adequately locomote, reaching a speed up to 3 body lengths.s(-1). Honeybees use their wetted wings as hydrofoils for their water surface propulsion. Their locomotion imparts hydrodynamic momentum to the surrounding water in the form of asymmetric waves and a deeper water jet stream, generating similar to 20-mu N average thrust. The wing kinematics show that the wing's stroke plane is skewed, and the wing supinates and pronates during its power and recovery strokes, respectively. The flow under a mechanical model wing mimicking the motion of a bee's wing further shows that nonzero net horizontal momentum is imparted to the water, demonstrating net thrust. Moreover, a periodic acceleration and deceleration of water are observed, which provides additional forward movement by "recoil locomotion." Their water surface locomotion by hydrofoiling is kinematically and dynamically distinct from surface skimming D. H. Marden, M. G. Kramer, Science 266, 427-430 (1994)], water walking D. W. M. Bush, D. L. Hu, Annu. Rev. Fluid Mech. 38, 339-369 (2006)], and drag-based propulsion D. Voise, J. Casas, J. R. Soc. Interface 7, 343-352 (2010)]. It is postulated that the ability to self-propel on a water surface may increase the water-foraging honeybee's survival chances when they fall on the water.